C_3F_6 플라즈마 중합에 의한 금속표면에 소수성 향상

소현,임대재,김영채 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.1

단량체인 hexafluropropene(C_3F_6) 기체를 플라즈마 증합하여 구리표면에 증착된 불소화합물이 표면 소수성 성향의 관점에서 조사되었다. 표면 소수성이 최대가 되는 조건을 찾기 위해 플라즈마 변수를 변화시켰으며 플라즈마 출력과 압력 증가에 따라 증착속도는 최대 60[㎍ cm^-2min^-1]를 나타냈다. 100W, 1torr, 10min의 공정변수에서 표면 자유에너지가 8.8[dyne cm^-1]로 물과의 접촉각이 127.75℃ 소수성 표면을 확인하였다. 플라즈마 증착된 표면은 CF, CF_2등의 불화탄소 기능기가 표면에 도포 되었으며 C/F 비가 2이하를 나타내었다. 구리표면에 형성된 불소화합물은 1㎛이하의 두께로 얇고 균일한 형태를 지니고 있으며 표면 조도의 증가가 접촉각을 더욱 상승시켜 구리표면이 합성고분자인 PTFE(108˚)보다 소수성이 향상되었다. Fluorocarbon, which was deposited on copper surface by plasma polymerization with monimer C_3F_6, was investigated from the point the hydrophobicity. Plasma parameterswere changed to find the maximum conditions of the surface hydrophobicity. Rate of deposition with increasing plasma power and pressure showed the value of 60[㎍ cm^-2min^-1]. It was found that the surface energy was 8.8[dyne cm^-1] and contact angel with water was 127.75℃ at the optimum conditions, 100W, 1torr, 10min. The surface with plasma deposition was coated fluorocarbon groups such as CF, CF_2 and C/F atomic ratio showed the value of less than 2. Deposited fluorocarbon indicated thin and homogeneous film with the thickness of 1㎛. Contact angels of plasma deposited Cu surface showed more hydrophobic than that of synthesis polymer PTFE(108˚).

개방 근첨 치아의 근관 충전방법에 따른 치근단 폐쇄효과에 관한 연구

소현,최호영,최경규,최기운,So, Hyun,Choi, Ho-Young,Choi, Kyung-Kyu,Choi, Gi-Woon 대한치과보존학회 2000 Restorative Dentistry & Endodontics Vol.25 No.3

The purpose of this study was to compare the leakage of four different obturation techniques in conjunction with immediate apical barrier of ${\beta}$-tricalcium phosphate(TCP) in teeth with open apex. Eighty single-rooted human premolar teeth were prepared and sectioned horizontally, so maximum diameter in apex was 4mm. Apical defects that were similar to open apex, were created with #1/2 round bur and SF104R bur. The apical foramen were opened to a size 80 file extended 3mm beyond the apex. The teeth were placed into the oasis block soaked saline to simulate periapical tissue often associated with pulpless teeth and received apical barriers consisting of TCP followed by obturation using lateral condensation technique, vertical condensation technique, continuous wave technique and thermoplasticized gutta-percha injection technique. Two unobturated teeth served as positive and negative controls. Teeth were immersed in resorcinol-formaldehyde resin for S days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then sectioned horizontally at 1.5mm(level 1), 2.5mm(level 2) and 3.5mm(level 3) from the apex, and examined under a stereomicroscope at ${\times}40$ magnification. The photographs were taken at ${\times}40$ magnification of the filling in each level and scanned. The leakage length in tooth/resin interface was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the leakage length of canal wall infiltrated with resin to the total length of the canal and was analyzed statistically(One-way ANOVA and Scheffe test). The result were as follows : 1. At the level 1, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), and the most leakage in the continuous wave technique group(group 3). There was statistically significant difference between the thermoplasticized gutta-percha injection technique group and the continuous wave technique group(p<0.05). 3. At the level 3, there was the least leakage in the thermoplasticized gutta-percha injection technique group(group 4), but there were no statistically significant differences between other groups(p>0.05). These results suggest that thermoplasticized gutta-percha injection technique which had 1mm apical gutta-percha matrix after the formation of TCP apical barrier, can demonstrate favorable apical sealing.

원거리 플라즈마에 의한 Photo-Resist 세정과 In-situ 표면 분석

소현,전형탁,김영채 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.3

원거리 산소, 수소 플라즈마를 이용하여 실리콘 웨이퍼 표면에 7,000Å 두께의 감광제(Photo-Resist: PR)를 제거하는 건식세정을 수행하였다. 실시간 질량분석과 in-situ XPS 분석으로 분해되는 유기화합물의 기상 및 표면 변화특성을 관찰하였으며, 표면온도, 유량, 플라즈마 출력과 노출시간의 공정변수 영향을 조사하였다. 최소공정 조건(130℃, 10sccm, 100W와 180초)에서 PR 분해속도가 4,500Å/min을 나타내었다. 산소 플라즈마는 유기화합물인 PR을 산화시켜 휘발성 물질로 전환시키는데 효과적이었으나 산소 라디칼이 실리콘 표면과 반응하여 산화막을 성장시키는 문제를 초래하였다. 따라서, 산소 플라즈마의 에싱(ashing)과정을 질량분석기로 모니터링하여 감광제를 제거한 후 수소 플라즈마를 적용하는 2단계 세정공정으로 실리콘 표면 위에 존재하는 유기화합물을 XPS 검출한계 이하로 제거하였다. 건식세정 후 평균 표면조도(RMS)가 2.93Å의 평탄한 표면을 확인하였고, 물리, 화학적 변화가 없는 세정이 가능하였다. Removal of photo-resist(PR) with the thickness of about 7,000Å on Si wafer was carried out by dry cleaning with using remote oxygen and hydrogen plasmas. During the removal process, the changes of surface and gas composition were monitored by real-time mass spectroscopy and in-situ XPS. Effect of process parameters such as surface temperature, flow rate, plasma power and exposure time has been investigated. The results showed that decomposition rate of PR was accelerated upto 4,500Å/min by the minimum process condition(130℃, 10sccm, 100W and 180 sec). Oxygen plasma effectively oxidized the PR into gaseous volatile compounds. However, oxygen radicals caused the growth of oxide layer. Therefore, two step process is proposed. Oxygen plasma ashing upto thin PR layer remained is followed by a subsequent cleaning with hydrogen plasma. The two step process removed carbon contaminants below the XPS detection limit, and substantially flat surface with mean surface roughness of 2.93Å.

초등학생의 스트레스와 스트레스 증상간의 관계

소현,정영숙 韓國學校保健學會 2003 韓國學校保健學會誌 Vol.16 No.1

The purpose of this study id primarily intended to examine the stress and physical, emotional and behavioral stress symptoms of elementary school students supply the basic data of intervention for children's health promotion. The subjects of this study were 616 students who were currently enrolled in 5th and 6th grade elementary school in Jeollabukdo ; 3 schools in J city and other 6 in 3 rural area. The data were collected by self-reported questionnaire form 3rd to 13th April 2002 and collected data were analyzed by SPSS WIN 8.0. The results of this study were as followings. 1. The mean score of stress that children experience was 2.73 and the most stressful factor was a friendship stress. The most frequently experienced stress were fell that a friends would leave them alone. 2. The mean score stress symptom that children experience was 1.92 and the most stressful symptom was the emotion symptom. The most frequently experienced stressful symptom were feel fatigue of everyday. 3. General characteristics related to stress were showed significantly different according to sex(t=-3.243, p=.001) 4. General characteristics related to stress symptoms were showed significantly different according to sex(t=-2.268, p=.024), family circumstances(F=8.697, p=.000, academic scores(F=11.216, p=.000) and parental concerns on a child(t=-2.561, p=.011). 5. The relation between stress and stress symptoms showed a positive correlation, which was significant statistically(r=.453, p=.000). In conclusion, elementary school students experience various stresses and the stress symptoms have positive close connection with health problems. Therefore, to study the students stress and consequent symptoms further, it is recommended that we should subdivide and analyze the stressor and stress symptoms by proper areas. In the meantime, in order to promote children's health using the data in this study, we should develop the correlated program among individual, family, school and community while we are deeply concerned about and support children continuously.

플라즈마 디스플레이 패널(PDP)의 방전과 열화공정에 따른 표면으로부터의 기상특성

소현,이상무,문세기,김영채 한국화학공학회 2004 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.42 No.6

플라즈마 디스플레이 패널(PDP) 내부 표면 변화 관찰

소현,이기형,김영채 한국화학공학회 2002 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.40 No.5

플라즈마 디스플레이 패널(PDP) 제조에서 에이징 공정은 표면 안정화를 위한 최종단계 이다. 방전에 의한 에이징 효과를 이해하기 위해 7인치 크기의 패널 내부를 분석하기 위한 in-situ 시스템을 고안하여, 에이징 시간에 따른 패널을 진공상태에서 해체하고 분석시스템으로 이송한 후 ESCA(Electron Spectroscopy for Chemical Analysis)로 측정하였다. 전면판의 MgO보호막은 초기 수분과 탄소 성분에 의한 Mg(OH)_2, MgCO_3의 화합물이 형성되어있어, 플라즈마 에이징 시간이 증가하면서 MgO형태로 화학적 변화하고 있다. 또한, 배면판의 형광체에 존재하는 탄소성분은 플라즈마에 의해 형성된 하전 입자의 스퍼터링에 의해 기기측정한계 이하까지 제거되었다. 전면판과 배면판의 변화는 12시간 이후 안정되었다. 이는 기존 최소 에이징 공정시간과 일치한다. Aging process for the surface stabilization is the final step in plasma display panel(PDP) fabrication. We designed and installed a in-situ analysis sytem to investigate the change of interior surface of 7-inch test panel. PDP was disassembled in the system and transferred to the in-situ electron spectroscopy for chemical analysis(ESCA) chamber without exposure. MgO protection layer on the front panel indicated the presence of Mg(OH)_2, MgCO_3 compounds due to the hydration and carbon incorporation on the panel. These compounds were converted to the MgO with increasing time of the plasma aging. Carbon impurity in phosphor on the rear panel was reduced to the level lower than detection limits of ESCA by sputtering of the radicals in the plasma after 12 hours of aging. ESCA analysis revealed that 12 hours of aging time is consistent with the time to stabilize the change interior surface.

사람 치수 세포와 치주 인대 세포의 유전자 발현에 관한 비교 연구

소현,박상혁,최기운 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.5

The purpose of this study was to characterize functional distinction between human dental pulp cells(PC) and periodontal ligament cells(PDLC) using cDNA micro array assay and to confirm the results of the microarray assay using RT-PCR. 3 genes out of 51 genes which were found to be more expressed(>2 fold) in PC were selected, and 3 genes out of 19 genes which were found to be more expressed(>2 fold) in PDLC were selected for RT-PCR as well. According to this study, the results were as follows: 1. From the micro array assay, 51 genes were more expressed (2 fold) from PC than PDLC. 2. RT-PCR confirmed that ITGA4 and TGFβ2 were more expressed in PC than in PDLC 3. From the micro array assay, 19 genes were more expressed (2 fold) from PDLC than PC. 4. RT-PCR confirmed that LUM, WISP1. and MMP1 were more expressed in PDLC than in PC. From the present study, different expression of the genes between the PC and PDLC were characterized to show the genes which play an important role in dentinogenesis were more expressed from PC than PDLC, while the genes which were related with collagen synthesis were more expressed from PDLC than PC. 본 연구는 사람 치수세포 및 치주인대세포의 차이를 알아보고자 배양한 각각의 세포를 CDNA microarray assay를 통하여 유전자의 발현정도의 차이를 비교하였다. 그 결과를 바탕으로 각각의 세포에서 2배 이상의 유전자 발현의 차이를 보이는 유전자중 특징적인 3가지 유전자를 선택하여 RT-PCR로 검증한 결과 다음과 같은 결론을 얻었다; 1. Microarray assay 결과, 치주인대 세포에 비해 치수 세포에서 2배 이상 발현한 유전자 수는 총 51개가 나타났다. 2. RT-PCR의 결과, 치주인대세포에 비해 치수 세포에서 ITGA4, TGF-β2 등이 높게 나타났다. 3. Microarray assay결과, 치수 세포에서 비해 치주인대 세포에서 2배 이상 발현한 유전자 수는 총 19개가 나타났다. 4. RT-PCR의 결과, 치수 세포에 비해 치주인대세포에서 LUM, WISP1, MMP1 등이 높게 나타났다. 본 연구 결과로 치수세포에는 상아질 형성에 관여하는 특징적인 유전자가 치주인대세포에 비해 높게 발현되었으며, 치주인대세포에는 교원질 합성에 관여하는 특징적인 유전자가 치수세포에 비해 높게 발현되어, 치수세포와 치주인데 세포는 유전자 발현의 차이가 나타남을 알 수 있었다.

저소득층 어머니-아동간 책읽기 상호작용

소현아,김명순 연세대학교 생활과학연구소 2000 生活科學論集 Vol.14 No.-

The purpose of this study was to explore low-income mother-child interactions during reading two types of children's picture books, a narrative book and a informational book. The subjects were 40 low-income mothers and their children at the age of the 3- and the 4-year-olds. While the mothers read aloud the books with their children, their interactions were videotaped. The data were analyzed by frequency, percentage, x^2 tests and paired-t tests. The results were as follows: First, the low-income mothers' verbal behaviors from the most to the least were statements, questions, and responses. The mothers frequently showed description, explanation, labelling statement, labelling questions and repetition feeback to their children. The children frequently used answers, labellings, and topic continuation statements. Second, the low-income mothers and their children showed more verbal behaviors during the informational bookreading than those during the narrative bookreading. The children used more labelling behaviors during the informational bookreading than those during the narrative bookreading.

Molecular Cloning and Characterization of Soybean Cinnamoyl CoA Reductase Induced by Abiotic Stresses

소현아,정은숙,Chang-Woo Cho,Kee-Young Kim,이재헌 한국식물병리학회 2010 Plant Pathology Journal Vol.26 No.4

Suppression subtractive hybridization was used to isolate wound-induced genes from soybean. One of the wound-induced genes, gmwi143 designated as GmCCR,showed high homology with genes encoding cinnamoyl-CoA reductase (CCR; EC 1.2.1.44). Deduced amino acid sequences encoded by GmCCR showed the highest identity (77%) with those of Acacia CCR. There are 2CCR genes highly homologous to GmCCR in soybean genome based on Phytozome DB analysis. RNA expression of GmCCR was specifically induced by local and systemic wounding, drought, high salinity or by ultraviolet stress. Our study suggests that GmCCR may be involved in resistance mechanism during abiotic stresses in plants.

Understanding and Utilization of Social Media Algorithms by Gen-Z Content Creators and Users - A Study of Reciprocal Relationship and Implications -

소현서,홍창표,손채현,김나경,김 동 환 디자인융복합학회(구.한국인포디자인학회) 2023 디자인융복합연구 Vol.22 No.2

This paper investigates the reciprocal relationship between social media algorithms and users, and the potential impact on the social media environment. As social media increasingly becomes an essential part of everyday life of Gen-Z, there are concerns about how its algorithms may influence users. We examine the extent to which users understand and use the algorithm, and the tactics they employ to do so. Additionally, we categorize users into content creators and content users, exploring how these questions apply to each group. By surveying 508 content users and conducting in-depth interviews with content creators, we provide both quantitative and qualitative data. Our findings indicate that users understand and actively manipulate algorithms to suit their preferences. We argue that algorithm designers must consider users' interests to ensure ethical and effective designs. This research has important implications for the future of algorithmic design.